1. Field of the Invention
The present invention relates to a transport ship having a hull includes a sheathing and a weather deck and having a front part, a rear part and a central part.
2. The Prior Art
A large number of different types of transport ships of the above-mentioned general kind are known in practice. Usually, the rear part of the ship includes a deck superstructure with the navigating bridge of the ship and the means necessary for the propulsion of the ship, including machinery and fuel tanks, while the front part of the ship includes the stem and store rooms, if any. The central part of the ship includes the hold, which is constructed in accordance with the specific type of goods to be transported. The hold may thus be constructed specifically for the transport of one specific type of goods, including e.g., cooled goods, liquid gas, dry cargo, oil or containers. Particularly in former times, the possibilities of utilizing transport ships for carrying combinations of the above-mentioned types of goods were very limited.
To achieve an increased flexibility of goods transport ships to a certain degree, the so-called Ro-Ro ships have been developed in the past twenty years, with a weather deck for the transport of particularly containers and with a plurality of tween decks that may be used for the transport of trailers or e.g., cars which may be loaded using stern ramps.
However, as far as the so-called refrigerator ships are concerned, specifically adapted to transport refrigerated goods, it has not been possible to achieve optimum flexibility and capacity in the past. In particular, the conventional structure of the refrigerator ships and stability deliberations have set a limit to the amounts of additional types of goods that can be carried and to the conditions under which such goods may be carried. Refrigerator ships are typically provided with an internal refrigerated hold over the greater part of the length of the hull, see e.g., European Patent Application No. 0 601 233, the refrigerated hold accommodating a relatively large number of tween decks with a small free height. The reason is that the goods are usually stored on pallets and do not stand stacking in the height. The goods may e.g. be bananas, lemons or vegetables which are to be kept refrigerated during the transport. The goods are typically cargoes which are to be transported over great distances, e.g. from South America to Europe.
In view of the above, it has been attempted to construct the refrigerator ships so as to enable them to carry standard containers which are stacked on the weather deck of the ship. This results in some increased flexibility, as the ship can then be utilized for the transport of refrigerated goods as well as a surface cargo, which may produce increased earnings per voyage. These refrigerator ships, however, are inexpedient, because certain loading situations give rise to stability problems during the voyage of the ship. These problems may occur when the ship, when bound for return, is to sail without refrigerated goods, but with a surface cargo, such as containers. Since the typical surface cargoes are formed by containers of a much greater weight than a corresponding volume of the refrigerated goods, stability deliberations set a limit to how high the containers may be stacked on the weather deck, also when sailing with refrigerated goods.
An object of the present invention is to provide an improved transport ship by means of which, with fewer stability problems, different combinations of goods may be transported, at least one type of which should preferably be capable of being transported in refrigerated form, while allowing greater amounts of the other goods to be transported at the same time. In this connection, different combinations of goods are taken to mean sailing with or without the refrigerated goods, and it must also be possible optionally to transport at least one other type of goods, particularly in the form of standard containers. This provides a high degree of flexibility, so that the owner of the ship can obtain greater earnings per voyage in relation to the known refrigerator ships.